2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/137638We extend the Mori-Zwanzig equations to the case where the Liouvillian is time-dependent by way of a Dyson identity due to Holian and Evans. This extension makes it possible to treat, for example, more general cases of continuous-wave (cw) or pulsed irradiation in NMR and coherent optics. The formalism immediately allows for reference frame changes and approximations based on coherent averaging.Chemical PhysicsAtomic Physicstext